Immunohistochemical expression of p14 MMTV env protein in feline mammary carcinomas.

<p>(A) FMC # 84471. Tubulopapillary FMC PCR-negative and negative for MMTV p14 expression (Immunoperoxidase-DAB, Bar = 100 μm) (B) FMC # 84589. Tubulopapillary FMC PCR-positive, a weak cytoplasmic immunostaining was detected in some neoplastic epitrhelial cells (Immunoperoxidase-DAB, Bar = 100 μm). (C) FMC # 80613. Tubolopapillary FMC, some neoplastic epithelial cells show distict cytoplasmic MMTV p14 labelling (Immunoperoxidase-DAB, Bar = 100 μm). (D) FMC # 86367. Solid FM, a large number of carcinoma cells show cytoplasmic p14 staining, Scattered inflammatory cells associated with neoplastic proliferation resulted MMTV p14-positive (Immunoperoxidase-DAB, Bar = 100 μm).</p

Multiple nucleotide alignment of the MMTV-like env gene sequences.

<p>A) The env sequences from two feline mammary tumors (indicated by their respective number) were aligned with NIH 3T3 (positive control for MMTV), mouse mammary tumor virus from HeJ mice, and HMTV (accession numbers AF228551.1 and AF243039, respectively). B) DNA sequencing, confirming the MMTV sequences. Surprisingly, one of them (Cat 87768) showed a polymorphism (c.7575 A> G), that cause aminoacyl substitution (Thr> Ala).</p

Determination of phylogentic relationships of Env sequences identified in different hosts.

<p>A neighbor-joining phylogenetic tree from nucleotide sequences of env of MMTV viruses. The tree was rooted to HERV-K. The robustness of individual nodes of the tree was determined by using bootstrap analyses of 1,00 replicates.</p

Loss of c-KIT expression in thyroid cancer cells

<div><p>Papillary thyroid carcinoma is the most frequent histologic type of thyroid tumor. Few studies investigated the role of c-KIT expression in thyroid tumors, suggesting a role for this receptor and its ligand in differentiation and growth control of thyroid epithelium and a receptor loss following malignant transformation. We investigated and correlated c-KIT expression levels and two known markers of thyrocytes differentiation, PAX8 and TTF-1, in malignant and benign cytological thyroid samples. Moreover, we performed functional studies on human papillary thyroid carcinoma cell line to associated c-KIT expression to thyrocytes differentiation and tumor proliferation. c-KIT and PAX8 expression resulted higher in benign samples compared to the malignant ones, and the expression levels of these two genes were significantly correlated to each other. We also observed that c-KIT overexpression led to an increase of PAX8 expression level together with a decrease of proliferation. Furthermore, c-KIT overexpressing cells showed a regression of typical morphological features of malignancy. Taken together these results suggest that c-KIT could be involved in the differentiation of thyroid cells and in tumor progression.</p></div

Table_1_Association of Mouse Mammary Tumor Virus With Human Breast Cancer: Histology, Immunohistochemistry and Polymerase Chain Reaction Analyses.docx

Purpose<p>The purpose of this study is to determine whether mouse mammary tumor virus (MMTV)-associated human breast cancer has the same or similar histology to MMTV-associated mouse mammary tumors. Such associations may indicate a role for MMTV in human breast cancer.</p>Methods<p>Immunohistochemical techniques (using antibodies directed against the signal peptide p14 of the envelope precursor protein of MMTV) and polymerase chain reaction (PCR) analyses were used to identify MMTV proteins and MMTV-like envelope gene sequences in a series of breast cancers from Australian women. The histological characteristics of these human breast cancer specimens were compared with MMTV positive mouse mammary tumors. The same methods were used to study benign breast tissues which 1–11 years later developed into breast cancer.</p>Results<p>MMTV p14 proteins were identified in 27 (54%) of 50 human breast cancers. MMTV env gene sequences were identified by PCR in 12 (27%) of 45 human breast cancers. There was a significant correlation between the presence of MMTV (identified by p14 immunohistochemistry) in human breast cancers and histological characteristics similar to MMTV positive mouse mammary tumors (p = 0.001). There was a non-significant correlation between the presence of MMTV env gene sequences (identified by PCR) in human breast cancers and histological characteristics similar to MMTV positive mouse mammary tumors (p = 0.290). MMTV p14 proteins were identified in 7 (54%) of 13 benign breast specimens that later developed into human breast cancers. MMTV by PCR was identified in two benign specimens one of whom later developed MMTV positive breast cancer.</p>Discussion<p>These observations offer evidence that MMTV may be associated with characteristic human breast cancer histology. p14-based immunohistochemistry appears to be a more reliable technique than PCR for the identification of MMTV in human breast cancer. Identification of MMTV-associated p14 proteins in benign breast tissues confirms prior PCR-based studies that MMTV infection occurs before the development of MMTV positive breast cancer.</p>Conclusion<p>Many MMTV positive human breast cancers have similar histology to MMTV positive mouse mammary tumors. MMTV infection identified in benign breast tissues precedes development of MMTV positive human breast cancer. When considered in the context of prior studies, these observations indicate a likely role for MMTV in human breast cancer.</p

Correlation between MMTV-like p14 expression and pathological findings of feline mammary carcinomas investigated.

<p>Correlation between MMTV-like p14 expression and pathological findings of feline mammary carcinomas investigated.</p

Fluorescent-PCR to detect MMTV-like sequence in feline mammary tumors.

<p>Fragment analysis show the blue peaks that represent the size of fragment (191bp) detected by capillary electrophoresis method.</p

Pathological features of the 53 canine and 86 feline mammary carcinomas examined.

<p>Pathological features of the 53 canine and 86 feline mammary carcinomas examined.</p

PAX8 overexpression in benign thyroid nodules.

<p>PAX8 mRNA expression in PTC (n = 39) and BN (n = 30) (FNAC) samples.</p

TTF-1 downregulation in benign thyroid nodules.

<p>TTF-1 mRNA expression in PTC (n = 39) and BN (n = 30) (FNAC) samples.</p